Conventionally, when an image is picked up telescopically or in a dark portion (in which long time exposure is required) in a handheld fashion, there is a possibility that “shake” such as hand shake and the like occur. To ensure reliable photography, there is widely known an image pickup apparatus having a so-called hand-shake correcting function mounted thereon to ensure reliable image pickup. The hand-shake correcting function is arranged such that when an optical axis is dislocated by shake applied to the image pickup apparatus by hand-shake and the like of a user, the dislocation of the optical axis is corrected by driving a shake correction optical system and an image pickup device according to the shake.
The image pickup apparatus on which the shake correcting function is mounted is provided with a shake detection sensor composed of, for example, a gyro for detecting a shake amount of the image pickup apparatus. A shake angle of the image pickup apparatus is calculated by integrating the output from the shake detection sensor, and the shake correction optical system and the like are driven based on the information of the calculated shake angle.
The shake detection sensor has a relatively large individual difference in a detection output when the image pickup apparatus is in a stationary state, and further since the detected output changes depending on an environmental temperature, the shake detection sensor is ordinarily connected to an amplifier through a high-pass filter composed of a capacitor and a resistor device so that a direct current component signal is eliminated from the output signal of the shake detection sensor.
In contrast, there is, for example, Patent Document 1 described below as a document relating to this technical field. The technology disclosed in Patent Document 1 relates to a camera on which a shake correcting function is mounted to correct movement of a subject image on a light receiving surface by calculating a shake amount of the camera from a signal output from an angular speed sensor and driving a correction optical system disposed in a light path of an image-pickup optical system based on the shake amount. The shake correcting function is composed of direct current cut means for cutting a direct current component included in the output voltage of the angular speed sensor, subtraction means for subtracting a direct current component voltage V3 from the output voltage V1 of the angular speed sensor, direct current detection means for calculating a direct current component by carrying out an arithmetic operation of (V3+V2/Kx) based on the output voltage V2 of the subtraction means, and setting means for setting a detection standard of the direct current detection means by changing the coefficient Kx, wherein the coefficient Kx is set to a relatively small value K1 during a period from a time at which a power is supplied to a time at which a light measuring switch is turned on so that a frequency component is cut up to a relatively high frequency component, the coefficient Kx is continuously changed toward a value K2 larger than the value K1 during a period in which a predetermined time has passed from the time at which the light measuring switch is turned on, and thereafter the coefficient Kx is set to the above value K2 so that only a relatively low frequency component is cut.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 8-82823